1. Field of the Invention (Technical Field)
The present invention relates to transporting external test experiments to and from orbit on the exterior of a reusable launch vehicle. More particularly, the present invention relates generally to external vehicle experiments, integration, transport to orbit, exposure in orbit, exposure to the external re-entry environment from orbit including instrumentation and testing apparatus and the return of various support hardware and experiment sample services used on reusable space transportation vehicles.
2. Description of the Related Art
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-à-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
The transportation of cargo to space is expensive. The secondary payload hardware has mass and minimum volume. Transporting the internal secondary payload hardware to and from orbit in an affordable manner is a goal consistent with life cycle costs and efficient logistics operations. The problem is the cost of the individual operations required to transport cargo to orbit. The part of the transportation operation can be addressed by the emerging reusable launch vehicles. Kistler Aerospace's secondary payload hardware research and development has proposed various additional aerospace structures and opened a new area of technology and commercial secondary payload hardware accommodation. Secondary payload hardware structures are a refined technology within the aerospace community. Unmanned activities in space are less expensive than manned activities. The unmanned aerospace reusable launch vehicle (RLV) can provide the secondary payload hardware technologies to smooth this process.
The traditional approach to manifesting of space launch systems has been hardware intensive, safety driven and long duration scheduling activities. The emerging commercial technologies point another way and attempt to be sensitive to commercial customer's launch on demand requirements.
Many previous space launch patents in prior art discuss reusable features, but none talk about external payloads designed to permit the testing of the materials required. The heating on the surfaces of the reusable launch vehicle are significant and require testing to develop a reliable reusable material and the testing environments for development. A typical simulation procedure requires several wind and arc jet wind tunnels to simulate, on the earth's surface, part of the re-entry environment experienced in an actual orbital re-entry.
U.S. Pat. No. 4,884,770 to Martin, issued on Dec. 5, 1989, describes a earth to orbit turbojet vehicle, but no mention of testing external surfaces on the exterior. U.S. Pat. No. 4,796,839 to Davis, issued on Jan. 10, 1989, describes an earth to orbit vehicle with recovery aspects, but no mention of testing external surfaces on the exterior. U.S. Pat. No. 4,265,416 to Jackson of NASA, issued on May 5, 19819, describes a earth to orbit reusable vehicles, but no mention of testing external surfaces on the exterior. U.S. Pat. No. 5,568,901 to Stiennon, issued on Oct. 29, 1996, describes a two stage earth to orbit reusable vehicle, but no mention of testing external surfaces on the exterior surfaces. Even U.S. Pat. No. 4,802,639 to Hardy, issued on Dec. 5, 1989, describes an earth to orbit turbojet vehicle, but no mention of testing external surfaces on the exterior.
U.S. Pat. No. 5,133,517 to Ware, issued on Jul. 28, 1992, uses an access door on the external tank, but fails to associate it to any exterior tests designed to provide samples for thermal protection system (TPS) analysis in the patent.
U.S. Pat. No. 4,650,139 to Taylor, issued on Mar. 17, 1987, attempts to alter the TPS on a partly reusable space launch vehicle, but enhance the aerodynamic flow by changing the re-attach point and injecting fluids into the slip stream, but no mention of returning sample for analysis or removing samples from the vehicle after re-entry. U.S. Pat. No. 4,790,499 to Taylor, issued on Dec. 13, 1988, expands the original patent, but fails to return any external samples.
The exterior sample return from the external tank (ET) of the space shuttle has been studied by NASA and their manufacturers in the 1980's, but the sample return from the ET requires removal of the samples from the ET after it has been taken to orbit. This involves altering the space shuttle mission trajectory, the salvage of the ET in orbit, a space walk by an astronaut for removal of the TPS samples from the ET, the restowing of the samples aboard a reusable segment of the vehicle and the proper disposal of the ET, which involves significant additional effort and expense.
Project Re-Entry II: Returning samples from Earth orbit at www.gvsp.usra.edu steps around the issue, but discusses low-cost sample return missions and has held two workshops, but doesn't mention using the return capsule and a test article for future mission for exterior materials or future samples for development by analysis of re-entry materials. The Ariane vehicle by the European Space Agency creates an Ariane Re-entry Demonstrator (ARD) testbed to re-enter from earth orbit, but is separate hardware and appears to have no exterior re-entry samples in the literature or pictures. Again it is the microgravity that is the focus of ARD rather than the phased testing approach with incremental development advances in materials technology based on systematic analysis of re-entry sample materials from actual re-entry missions.
Even the Orbital Science Corporation Pegasus alludes to leading edge research into thermal protection systems on www.orbital.com and some of their technical papers and literature details missions for spaceplanes, but all seem to cost an entire mission instead of the full instrumentation tests with sample back for analysis in an incremental development manner. Prior art uncovered to date is not directly germane to the present invention.
The space station attempts to address the exposure of experiments to the space environment, see Brian Berger's article, “NASA Aims to Finish Express Pallet As Costs Stiffe Brazil's Plans,” SPACENEWS Aug. 26, 2002, 1p, Springfield, Va., USA. The Express Pallet does not address either cycle through the atmosphere, however. Astrocourier (USA) addresses a similar commercial market, but also does not offer either cycle through the atmosphere, however.
Accordingly, it can be appreciated that there is a great need for a cost effective, reliable, efficient, and safe hardware systems using integrated technologies containing subsystems common with the reduced cost hardware solutions. The present invention provides this and other advantages, as will be apparent from the following detailed description and accompanying figures.